1. Field of the Invention
The present invention relates to medical devices, and more particularly, to a tympanostomy tube (ear tube) device used in connection with the insertion of an ear tube into a patient, and methods for softening and dissolving an ear tube on-command and without the need for anesthesia.
2. Description of the Related Art
Ear tube insertion, also known as tympanostomy or myringotomy tube insertion, is a surgical procedure for placement of a pressure equalizer tube into the tympanic membrane of the middle ear. This surgical procedure cures middle ear fluid and dramatically improves otitis media—the most common bacterial infection of early childhood. Middle ear fluid and otitis media can cause significant hearing loss and can lead to speech delays and severe ear infections. Tube insertion is particularly effective in treating otitis media because the tympanostomy tube permits the flow of antibiotic ear drops formulations into the middle ear and simultaneously allows infected ear fluid to drain out.
The first plastic tympanostomy tube was introduced in 1954. For the past 59 years there have been only minor advances in ear tube design. Current ear tubes are composed of common fluoroplastics, silicone, Teflon, or stainless steel. Ear tubes are essentially foreign bodies, which either fall out of the ear spontaneously or must be surgically removed. Normally, the tube self-extrudes from the ear as the tympanic membrane heals. If the tubes do not fall out of the eardrum after 2 to 3 years of observation, the child then undergoes a second surgery for removal.
More recently, biodegradable ear tubes have been studied by researchers. A dissolvable ear tube addresses the problems caused by the current generation of plastic tubes. Because dissolvable ear tubes do not have to be surgically removed, there is no need for further anesthesia to remove a tube that does not fall out of a child's ear on its own. Also, a biodegradable tube provides the potential benefit of lower perforation rate from a tube that stays in too long while awaiting spontaneous extrusion. However, these biodegradable tubes are designed to dissolve in the presence of body fluid, which may lead to problems. For example, biodegradable tubes begin to lose their mechanical integrity from the moment of insertion. The degradation rate is also difficult to predict because the moisture level of the middle ear varies with infection rates and amount of treatment. Further, the biodegradable tubes that have been developed dissolve too quickly to be effective and disintegrate well before the one year necessary to treat standard otitis media.